毛发湿度计测湿原理是根据脱脂后毛发随空气湿度变化而伸缩的（）特性制成的。
A.化学
B.物理
C.生理
D.电子
参考答案：B
Only after they had discussed the matter for several hours a decision .
A．they reached
B．did they reach
C．they reach
D．do they reach
一为迁客去长沙，西望长安不见家。这首诗的作者是谁？
